Analytical Study on a Flexible & Robust Manufacturing System

Nitish, Dr. Ravindra Kumar Sharma, Dr. Harish Kumar

Pallet, ntermediary, conveyor, transportation, constraints.

A pallet from any of its entries to any of its exits, in each case one pallet at a time. Each of the intermediary switches has two entries and one exit at the left-hand side, while at the right-hand side there are two exits and only one entry. An arrangement of standard modules as in Fig. 1 makes it possible for a pallet to either enter a machine through the lowermost conveyor or else bypass the machine through the middle conveyor. After having bypassed a machine through the middle conveyor, a pallet has two options: it can either proceed in a forward direction to a subsequent machine or move backwards using the topmost conveyor. If, for instance, the lowermost conveyor is already occupied, preventing a pallet from entering the target machine, then the pallet can move backwards and forwards in a circle until the lowermost conveyor is available again. In this way, the entire transportation system serves as a flexible buffer. Most transportation systems induce specific constraints on the flow of material; that is, the sequences in which pallets may visit machines. Let M and M0 be two machines. If in the transport system there is a path from M to M0 then there may be a material flow from M to M0; otherwise, a material flow from M to M0 is impossible. A layout such as the one depicted in Fig. 1, however, does not impose any constraint whatsoever on the material flow; between any pair of machines, there may be a material flow in either direction. For performance reasons, it is often convenient to impose some constraints anyway.